The proposed research plan is to operate a Center for Population Research (P30) within The Laboratory of Human Reproduction and Reproductive Biology (LHRRB) to foster the acquisition of knowledge that can ultimately be applied to the control of fertility and the reduction of reproductive disease and disability. This biomedical population research will be conducted in a coordinated INTERDISCIPLINARY manner including the biomedical, physiological and morphological aspects of ovarian, testicular, neuroendocrine, blastocyst and early embryonic function. This work is carried out largely in material derived from mammals (including the human) applicable to human biology. This research involves for example: STRUCTURAL and MOLECULAR changes in the plasma membrane of granulosa cells, initiation and maintenance of MEIOSIS in the oocyte, the role of ACTIN an MYOSIN in CYTOKINESIS, factors determining the nuclear shape and function of SPERM, mitogenic peptides in the testis, control of blastocyst fluid and swelling, steroid metabolism in the brain, ovary and testis, sertoli cell function, CONADOTROPHIC CONTROL of the testis and ovary, reproductive and SEXUAL BEHAVIOR, molecular events in DNA FUNCTION, membrane changes in the ACROSOME REACTION and sperm cell surface topography. The shared CORE FACILITIES and services funded by the Center for Population Research grant and other LHRRB resources provide electron microscopy, histology, photography, radioimmunoassay, computer services, electron probe, mass spectroscopy, high pressure liquid chromatography, amino acid analysis, animal facilities, central administration, a seminar program, central glasswashing, and a machine shop. The shared core services and facilities provide coordination of research, fosters interdisciplinary collaboration, and enhances QUALITY CONTROL, PRODUCTIVITY and COST EFFECTIVENESS.